SCATTERING FROM INHOMOGENEITIES INSIDE A FIBER WAVE-GUIDE

The interaction of surface guided modes with scatterers inside a fiber dielectric waveguide is studied analytically. A volume integral equation technique, based on Green's function theory for fiber boundaries, is used to formulate the problem. For the case of spherical scatterers, an analytical solution is developed by using an expansion in spherical vector wave functions, when b(k//1 minus k//2) less than 1, where (k//1 minus k//2) is the difference between the wave numbers of the fiber and the spherical scatterer whose radius is b. Expressions are obtained for the reflection, transmission, and radiated-field quantities up to the order of left bracket b(k//1 minus k//2) right bracket **5. Numerical results are computed and presented for several cases. Coupling between even-odd HE//1//1 modes is treated also.